In Shakespeare’s Sonnet 2, the speaker (presumably Shakespeare or an older poet) is giving advice to a younger man. The speaker notes that the younger man’s beauty will fade over time (40 years, or 40 winters), so it would be best to accept this fact instead of clinging to the idea that his youthful beauty will last forever. The only way to carry on this legacy of youthful identification is to procreate: to have children. In this way, the “beauty” the speaker is referring to could be physical beauty, honorable character, and/or the family name and all that is associated with the family name.
For your essay, you might want to mention the idea that physical (or superficial) beauty will be lost with old age. Focus more on the idea of legacy or what parents pass on to their children. The idea of being immortalized in poetry is analogous to being immortalized via successive generations of family. I get, from this sonnet, that there is a sense that the parent doesn’t just pass on physical traits and moral lessons to his child; that parent also lives vicariously through the child’s eyes, as if he (the parent) is made new (youthful) again by witnessing the child’s experiences.
Thank you very much